Chromic acid and pulverulent metal in a liquid medium have heretofore been applied to metal substrates followed by baking to attain a corrosion-resistant coating, such as disclosed in U.S. Pat. No. 3,687,738. Such compositions further containing organic substance and with zinc flake being representative of useful pulverulent metal have been shown in U.S. pending application Ser. No. 370,437, now U.S. Pat. No. 3,907,608.
Heretofore, the flake has been prepared without regard to coating composition needs. Hence, the commercially available flake concentrates have not been suitable for direct incorporation in the chromic-acid-containing coating compositions. Thus normal filtration operations subsequent to the flaking process, and drying to remove the incompatable organics, have been employed. Then, in coating composition preparation, fresh, compatible organic substance is needed for supplying the needed organic liquid to the composition.